just letting money fly out the open window

FV would be so ashamed of me!! It is always cold in my DS's room. I assumed it was because he is on the corner of the house and has 2 windows. Well, this morning while changing his diaper, I decided the window must be broken, because it was unbelievably cold in front of it. I went to figure out what to do, and realized the window was cracked open. It has been this way for probably 6 months. HOW MUCH HEAT DID I LOOSE DUE TO MY OVERSITE? Well, it is closed now!!!